Ichthyosis fetalis in a cross‐bred lamb

Background Ichthyosis is a dermatological disease characterized by varying degrees of generalized hyperkeratosis and alopecia. Two congenital forms of ichthyosis are recognized in animals: fetalis ( IF ) and congenita. The disease occurs rarely in cattle, swine, dogs, chickens and a goat; it has not been reported in sheep. Hypothesis/Objectives To provide clinical, laboratory and pathological assessments of a case of IF in a cross‐bred lamb. Animals A male cross‐bred lamb. Results Physical examination revealed apathy, fever, ectropion and eclabium. Generalized thickening and scaling of the skin was noted; this was most severe on the face, ears, inner thighs, limbs and perineum. Deep fissures and wounds were present on the hind limbs and forelimbs. The lamb was monitored for 75 days. During this period, lesions progressed and occasionally obstructed the nostrils and increasingly made it difficult for the lamb to flex major limb joints. Postmortem findings included severe epidermal thickening, multiple subcutaneous abscesses, ectropion and corneal scars. Histological findings revealed diffuse orthokeratotic hyperkeratosis, follicular keratosis, irregular epidermal hyperplasia and atrophy of the sebaceous glands. Serum vitamin A concentration was within the normal range for the species. Conclusions and clinical importance This case report describes a case of presumptive ichthyosis fetalis in a lamb. Greater awareness by practitioners is required for this disease to be included in the differential diagnosis of dermatopathies in this species.